Bulldozer having a universal blade mounting



ApriH 19, 1966 w, 0, JR 3,246,406

BULLDOZER HAVING A UNIVERSAL BLADE MOUNTING- Filed June 27, 1965 5 Sheets-Sheet 1 B0 5 5 2 1% My as J $5 34 A W O I M I!!! I f I 210 INVENTOR.

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April 19, 1966 W. O. RAY, JR

BULLDOZER HAVING A UNIVERSAL BLADE MOUNTING 5 Sheets-Sheet 5 Filed June 27, 1963 April 19,1966 w. o. RAY, JR 3,246,406

BULLDOZER HAVING A UNIVERSAL BLADE MOUNTING Filed June 27, 1963 5 Sheets-Sheet 4 J6? J4@ J58 J58 INVENTOR.

April 19, 1966 W. O. RAY, JR

BULLDOZER HAVING A UNIVERSAL BLADE MOUNTING 5 Sheets-Sheet 5 Filed June 27, 1963 INVENTORv emjfay ...f Z %&

United States Patent ice 3,246,406 BULLDOZER HAVING A UNIVERSAL i BLADE MOUNTING Willie ()dgen Ray, Jr., Jackson, Miss., assignor to M-RS Manufacturing Company, Flora, Miss, a corporation of Delaware Filed June 27, 1963, Ser. N0.'291,l97 Claims. (Cl. 37-144) This application is a continuation-in-part of my copending application Serial No. 251,867, filed January 16, 1963, now abandoned.

This invention relates to the art of earth moving machinery, and more particularly to an adjustable moldboard dozer.

An essential requirement of dozers or bulldozers is that the dozer blade or moldboard must be mounted quite rigidly to the frame of the machine. On the other hand, the blade or moldboard must be adjustable in various respects if a desirable versatility of the machine is to be obtained.

The usual rigid connection of the moldboard to the supporting arms which are pivoted to the frame of the machine back some distance from the front thereof causes the pitch of the moldboard to vary as the moldboard is lifted. Since dozer blades or moldboards generally are of a concave configuration on the front, this variation in pitch (angle which the blade makes with the ground) tends to-cause the moldboard to act somewhat as a hopper, whereby much 'of .the material which it has been pushing is not properly dropped. Furthermore, the optimum pitch will vary in accordance'with the type of material being dozed. Accordingly, it will be apparent that-thepitchof the dozer blade or moldboard should be adjustable.

When initially substantially level ground is being further leveled, the side-to-side tilt of the blade need not be changed. It should be substantially level with the machine. On the other hand, there are many situations, such as leveling a hillside for a roadway or the like in which the finished surface is relatively tilted quite substantially relative to the initial surface. For this to be effective, there must be a'tilt adjustment to the moldboard, and this has generally been thought to be incompatible with the requisite rigidity.

Finally, it will be realized that the angle (as viewed .from the top) which the dozer blade or-moldb oard makes with the direction of travel of the machine should be variable in accordance with the type of material being dozed, and in accordance with whether it is desired to 'push all of the material ahead of the blade, or to push it off to one side. 7

Generally speaking, the variation in pitch, tilt, and angle haveheretofore been thought to be incompatible with the requirement of rigidity. The problem is further compounded by the realization in the industry that steerable, rubber-tired bulldozers are generally .superior to the older, crawler treadvehicles. The steerable front wheels of the newer machines require clearance for turning of the front wheels, and this has not been a problem with the crawler tread machines which are now approaching obsolescence.

,Accordingly, it is an object of this invention to provide a dozer wherein the blade or moldboard is mount- 3,246,406 Patented Apr. 19, 196.6

ed to the machine with the requisite rigidity, and wherein the blade is adjustable.

More particularly, it is an object of this invention to provide a rubber-tired, steerable wheel bulldozer wherein the dozer blade or moldboard is adjustable for pitch, tilt, and angle.

Yet another object of this invention is to provide an adjustable blade bulldozer wherein the blade is affixed to rigid arm mounting means by a ball-and-socket connection.

Yet another object of this invention is to provide bulldozer blade or moldboard supporting means comprising a single rigid arm transversely spanning the machine.

It is yet another object of this invention to provide an adjustable moldboard bulldozer as heretofore set forth wherein all of the adjustments are effected from the operators seat and without the necessity of shutting down the machine.

Other and further objects and advantages of the present invention will be apparent from the following description when taken in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view of a bulldozer constructed in accordance with the present invention, parts being broken away for clarity of illustration;

FIG. 2 is a fragmentary rear perspective view on an enlarged scale showing the mounting of the dozer blade or moldboard;

FIG. 3 is'a fragmentary front view with the dozer blade or moldboard shown in broken lines, as taken along the line 33 in FIG. 2;

FIG. 4is a fragmentary top view showing some of the mounting ofthe .moldboard to the dozer;

FIG. 5 is a fragmentary longitudinal sectional ,view on an enlarged scale as taken along the line 5 -5 in FRIG. 1;

FIG. 6 is an enlarged detail sectional view, taken through a main connection between the support arm and moldboard, as taken along the line 6-,6 in FIG. 4;

FIG. 7 is an enlargeddetail sectional view as taken alongthe line 77 in FIG. 5;

FIG. 8 is an enlarged detail sectional view as taken along the line 38 in FIG. 5;

FIG. 9 is an exploded perspective ,view of the support arm and the moldboard as taken from the rear thereof;

FIG. 9a is a detail corresponding to a portion of FIG. 9 and; showing a modification thereof;

FIG. '10 is an enlarged sectional View as taken along the line 1il10 in FIG. 5;

FIG. 11 is a rear perspective view showing one of the connecting parts seen in FIGS. 9 and 10;

FIG. 12 is an enlarged detail view showing the part cooperable with the mounting structure of FIG. 11;

FIG. 13 is a rear perspective view of a moldboard or dozer blade incorporating amodificat ion of the invention;

FIG. 14 is a correspondingperspect-ive view of a modified form of the lower push frame;

FIG. 15 is a horizontal cross sectional view taken along the line 15-15 in FIG. 13 with the parts in assembled relation; and

FIG. 16 is a perspective view of the swivel connection between the push frame and the moldboard.

Referring now in. greater particularity tothe drawings, and first to FIG. v1, there will be seen a bulldozer-identi- .3 fied generally. by the numeral and including a tnacto-r 22 of the type having a pair of rear wheels 24 for driving the tractor, and a pair of steerable front wheels 26. The rear wheels also may be steerable. The front wheels are controlled by a steering wheel 28 at the operators station 30, this station also including the usual seat 32, and various hydraulic control levers and the like (not shown).

The bulldozed further is provided with a bulldozer blade or moldboard 34 of generally conventional construction, including a scraping or cutting edge 36, and a generally concave wall 38. The wall is braced around the back by peripherally disposed channel shaped members (FIGS. 2, 5 and 9) by intermediate vertically disposed channel shaped members 42, and by end walls 44. The moldboard is supported from the tractor by a lower push frame 46 (see FIGS.l-5 and especially FIG. 9) pivotally mounted at the rear corners thereof at 48 to depending brackets or the like 50 on the frame 52. The brackets 50 and pivots 48 are spaced back a short distance from the front of the tractor 22, and are disposed forwardly of the axles of the front wheels 26.

The lower push frame 46, as best may be seen in FIG. 9, is of generally rectangular outline, being welded of heavy sheet material. The frame is provided with a pair of rear lugs or ears 53 having apertures 54 therein by means of which the frame is pivoted at 48. At the left front corner, the frame is provided with a forwardly projecting lug or ear 56 having a transverse aperture 58 therein.

At the right front corner (see also FIG. 6) there is a forward projection 68 formed at its front end with a socket 62 therein, and having a peripheral flange 64 provided with appropriate bolt holes. The confronting lower portion of the reinforcing channel 40 is provided with a rearwardly protruding ball 66 having a reduced neck portion or spacer 68' A collar 72 with appropriate bolt holes therein surrounds the reduced neck or spacer portion 68. The collar is of small enough internal diameter to prevent retraction of the ball, and the collar is held against the front of the extension by bolts 74 extending through the bolt holes in the collar and in the flange 64, and having suitable nuts secured thereon. The dozer blade or moldboard thus is swivelly held to the right front corner of the lower push frame.

The forward extension 56 of the lower push frame 46 is adjustably mounted to the back of the dozer blade or moldboard 36 by means including a bracket 76. The bracket 76 is seen in FIGS. 2-5, and is best seen in FIGS. 9-11. The bracket includes a base plate 78 secured as by welding to the reinforcing channel 48 in symmetrical position relative to the ball 66. The bracket further includes a pair of curved parallel plates 80 perpendicular to the base plate 78 and reinforced by a plurality of triangular gussets 82 welded in place between the walls 80 and the base plate 78. An additional underlying support 84 may be seen in FIG. 11 between the blade wall 38 and the base plate 78. Confronting retaining flanges or teeth 86 are provided along the outer edges of the curved sidewalls or plates 80, the radius of curvature of each of the plates 88 is taken about the ball 66 as a center.

A clevis 88, shown in its normal relative position in FIG. 9, and twisted from this postion in FIG. 12, is received for up and down sliding movement in the bracket 76. In particular, the clevis 88 fits between the sidewalls or plates 88, and between the base plate 78 and the confronting flanges 86. The clevis has a pair of curved or arcuate sidewalls 90, one of which is concave on its outer face, and one of which is convex, respectively to conform to the confronting faces of the sidewalls or plates 80, as best seen in FIG. 10. The inner faces of the two sidewalls 96 are parallel and the lower push frame extension 56 is received between these plates on a pivot pin 92 held in place by a set screw 94 in one of the walls 90. The walls 90 are held in parallel spaced relation by a web- 96 which may be welded thereto, or which may be integral therewith.

The walls M) are provided with upstanding, generally triangular brackets 98 having confronting frusto-conical portions 100 with a pivot pin 102 secured therein by means of a set screw 104 in one of the brackets 98. A ball 106 is received on the pin 102 between the frustoconical projections 100, and swivels thereon a connecting member or plate 108 welded or otherwise suitably secured to the end of a piston connecting rod 110.

The piston rod 110 extends from a cylinder 112 (FIGS. 2-5) having an upstanding car 114 at the uper end thereof. The ear is apertured to receive a pin 116 passing through the side flanges 118 of a bracket 120 secured to the upper transverse portion of the peripheral reinforcing channel 40. Spaces 122 are provided about the pin to centralize the car 114 between the flanges 118. The hydraulic cylinder 112 is provided with hydraulic connections 124 leading to a suitable source of hydraulic pressure on the tractor 22, and controlled from the operators seat.

As will be apparent, extension and retraction of the cylinder 112 will cause the bracket 120 to be raised and lowered relative to the clevis 88. Since the clevis 88 is secured to the lower push frame 46, it cannot move up or down (except as the frame is pivoted up or down) and hence the dozer blade or moldboard 38 pivots up or down about the ball 66 and socket 62 to change the tilt of the blade or moldboard.

It will be appreciated that the arcuate movement of the clevis 88 requires a slight side-to-side movement of the hydraulic piston and cylinder arrangement 112. The ball connection between the connecting rod 110 and the clevis 88 facilitates this movement. Although not specifically illustrated, it will be appreciated that the upper pivotal connection of the piston and cylinder 112 to the pin 116 is also a ball type connection to allow the necessary side-to-side pendant movement.

The angle of the blade may also be adjusted by the connection to the clevis 88, and in accordance therewith, reference should be had to FIG. 9a. The parts in FIG. 9a are similar to those heretofore shown and described, and similar parts are identified by like numerals with the addition of the suffix a. FIG. 9a is only a fregmentary perspective view, since only a part has been changed. In

particular, the lower push frame 46a remains generally the same as heretofore, except that the left front extension 56a comprises an extensible portion 126 in which the aperture 58a is provided. The extensible portion 126 is telescopically movable in a sleeve portion 128 by means of an hydraulic piston and cylinder 130 mounted within the lower push frame, and connected to the extensible portion 126 by connecting rod 132. Suitable hydraulic connections are provided to the cylinder 130 from the source of hydraulic pressure in the tractor, and under the control of suitable controls at the drivers position. Extension and retraction of the extensible member 126 moves the left end of the dozer blade or moldboard away from and back toward the tractor, again with a pivotal movement about the ball 66 and socket 62, whereby the blade angle is obviously adjusted.

The front-to-back pitch of the dozer blade or moldboard is controlled by an upper strut 134. The upper strut comprises an hydraulic cylinder and piston having a lower, preferably fixed connecting rod 136 pivotally connected to a bracket 138 mounted at the front of the tractor frame 52 and extending up a short distance therefrom to the pivot pin 152. Additional details on the pivotal connection will be set forth shortly hereinafter.

At the front, upper end, the cylinder and piston are provided With a preferably movable connecting rod 142 pivotally mounted at 144 to a bracket 146 mounted on the top of the dozer blade or moldboard centrally thereof. Suitable hydraulic connections are provided to this cylinder from the source of hydraulic pressure in the tractor, under the control of suitable controls at the operators station. It will be apparent that extension or retraction of the upper strut 134 will tip the blade or moldboard frontwards or backwards about the ball 66 and the pivotal connection at 92 to the front left projection or extension 56 of the lower push frame 46.

Details on the lower pivotal connection to the bracket 138 may be seen in FIG. 8. The bracket 138 comprises a pair of side flanges 148 in parallel, spaced relation, and having at the 'upper ends a pair of confronting frustoconical projections 150. A pivot pin 152 extends through the frusto-conical projections, and carries a ball 154 between confronting ends thereof. The pin preferably is held in place by a set screw (not shown) in one of the projections. The connecting rod 136 is provided with a flattened extension 156 having an aperture therein receiving the ball 154. This ball type connection, as will be appreciated, allows a certain amount of side-to-side movement, as well as up and down, and is required by changes in orientation of the blade. Although specific details are not shown thereon, it will be understood that the upper pivotal connectionat 144 is a generally similar ball type connection. As will be seen in many of the figures, particularly including FIGS. 4 and 9, the bracket 146 includes a pair of parallel, spaced apart side plates or flanges 158 braced by suitablegussets 160. 'Frusto-c onical projections 162 center a flattened member 164 forming an extension of the connecting rod 142, this member preferably being received on a ball on the pivot pin 144, thus to allow a certain amount of lateral swivelling.

Finally, means is provided'for raising the dozer blade or moldboard from contact with the ground, or, on occasion, applying extra'force down on the blade causing it to dig in. This means comprises a pair of lift cylinders 166 extending diagonally downward from a position near the top corners of-the tractor to brackets near the lower portion of the moldboard.

More particularly, the-tractor has heavy vertical frame members 168 (FIGS. l-3 and 5) joined at the top to upper horizontal frame members 170. Brackets 172 are mounted thereon. As shown in detail in FIG. 7,'such brackets include heavy spacer blocks 173 and outer flanges 174 spaced therefrom by upper webs 176. A pivot pin 178 is tipped slightly from horizontal, and is provided adjacent "its center with a ball 180 between spacers 182. The ball pivots or swivels a flattened extension 184 at the top of a respective cylinder 166.

At the lower, forward end, each cylinder 166 is provided with a connecting rod "186. The connecting rods 186 have flattened members 188 at their extremities, which preferably are connected by ball connections, similar to those previously described, to pivot pins 190 carried by brackets 192 fixed on the moldboard immediately above the-lower portion of the peripheral reinforcing channel 40. As will be apparent, each bracket 192 comprises a pair of spaced-apart flanges 194. Extension and retraction of the cylinders 166 causes loweringandraising of the moldboard, as will be apparent.

An additional feature of the dozer blade or moldboard is to be seen in particular in FIGS. 2 and 5. On the bottom of the moldboard substantially immediately below the brackets 192, there are provided brackets 196 to which are pivotallyconnected shoes 19%. Each shoe comprises a flat floor portion 201), with an upturned trailing flange 202, and an upturned leading flange 204. The upturned leading flange is provided with an upstanding support 206 relatively adjacent each of the forward corners thereof ed with a plurality of apertures 214, and a pin 216 passes through a pair of apertures in the bracket 218 on the back of the peripheral reinforcing channel 40 immediately below the bracket 192 on each side, and through any selected one of the corresponding holes or apertures 214, whereby to vary the height of the shoe 198. The height of the shoe may be varied to determine the depth of cut of the blade or moldboard 34.

It will now be apparent that there has beenherein disclosed an improved bulldozer wherein the moldboard is rigidly attached to the frame of the tractor. The pitch of the moldboard or dozer blade does not change appreciably as the blade is lifted, due to the relatively short length of the lower push frame 46, and the relation of the upper strut 134 thereto. However, since a perfect parallelogram is not formed, there will be slight variation in pitch, and this is readily compensated for by changing the length of the upper strut 134 hydraulically. This is most simply accomplished by the operator with manual controls at the operators station, and in most instances, this is all that will be necessary, since the pitch changes to such a relatively limited degree that little trouble is encountered. However, his to be borne in mind that automatic controlscould be provided for varying the extension of the upper strut 134 in accordance with the degree to whichthe blade is :lifted; such automatic controls are not shown as theyare well known in the art.

Along with the great rigidity, adjustments as to pitch, tilt and angle are provided, all of which are operable from the operators seat or station, withoutthe necessity of stopping themachine, or dismounting on the part of the operator.

A modification of the inventionwhich has been found to be highly desirable from a commercial standpoint is shown in FIGS. 13-16. Most of theparts are similar to those heretofore shown and described, and consequently are identified by like numerals withthe addition of the suffix b, thereby to avoid .prolix and repetitive disclosure. The essential difference in the modification is that the ball-and socket connection 66, .62 has been supplanted by a swivelling construction which is atleast equally satisfactory, but which is considerablysimpler and less expensive to construct and install.

The swivellingconnection is provided by itself-aligning hearing or bushing assembly 220 shown in FIG. 16. This type of bearing is known per se, and includes an outer generally cylindrical member 222 having'an inner surface 224 in the form 'of a spherical segment, and an inner member 226 having an outer surface228 also in'thefor'rn of a spherical segment. The outer'surface 228'is convex is nature, while the inner surface 224 is concave and complementary to the convexsurface'228. The outer surface of the outer member 222 is provided with a cir cumferential groove 230, while the inner surface 232 of the inner member 226 is provided with an annular groove 234.

It is frequently the case with bearing members such as those just described to rely on the members only for axial skewing relative to one another, and to provide a sleeve bearing, or even anti-friction bearings .within the inner member 226. This can be done inthe present case,.it

so desired, but generally is'not necessary, since there is only a limited pivoting up'and down movement, andnot a continuous rotation. Thus, the innermember 226 is received on a pin 236 (FIG. 15) received between av pair of cars 238 of a bracket 240 (see also FIG. 13). The

ears are provided with reinforcing gussets 242, and also with generally frusto-conical protuberances 244 on the inner faces thereofwhich position theinner bearing, member 226.

.The outer member 222 of the bearing or bushing assembly, which conventionally is made in two pieces, as will be understood, to allow assembly with the inner member, is received in an aperture or eye 246 at the right front corner 60b of the lower push frame 46b. To insure 7 against endwise movement therein, the outer member may be secured by means of a set screw 248 extending into the groove 230.

Operation of the bulldozer remains exactly as described heretofore. The inner and outer members of the bearing or bushing assembly 220 skew relative to one another readily, and may also rotate relative to one another, or a bearing sleeve may be provided to avoid such rotating or pivoting, as heretofore described. In any event, universal movement is permitted within some limits, and operation is obtained which is fully as satisfactory as with the form of the invention as heretofore shown and described. However, fabrication is much simpler, and hence less expensive, particularly bearing in mind that the hearing or bushing assembly is a standard item readily available in commerce.

It is to be understood that the specific illustrative examples of the invention are for purposes of disclosure only, and are not be considered as limitative. Various changes will no doubt occur to those skilled in the art, and. will be understood as forming a part of the inven tion insofar as they fall within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. A bulldozer comprising a tractor having at least four wheels, at least two of which are steerable, a dozer blade, a lower push member of substantially rectangular configuration pivotally connected at two horizontally spaced connections to said tractor adjacent the front thereof, said push member having two horizontally spaced connections to said blade at'the front of said push member and adjacent the bottom of said blade, one of the push member connections to the blade comprising a universal connection, the other connection between the push member and the blade comprising a slide pivotally connected to said push member and received in a generally upwardly extending track section on said blade, said track section being arcuate about said universal connection as a center of radius, extensible means acting substantially vertically between said slide and said blade for varying the tilt of said blade about said universal connection, an extensible connection pivotally connected to said blade adjacent the top thereof and pivotally connected to said tractor ad jacent the front thereof for varying the pitch of said blade about'the' connections between said push member and said blade, and further extensible means pivotally connected to said blade and pivotally connected to said tractor for raising and lowering said blade.

2. A bulldozer as set forth in claim 1 and further including an extensible connection between said slide and said push member for varying the angle of said blade about said universal connection.

3. A bulldozer comprising a tractor having at least fourwheels, at least two of which are steerable, a dozer blade, a lower push member of substantially rectangular configuration pivotally connected at two horizontally spaced connections to said tractor adjacent the front thereof, said push member having two horizontally spaced connections to said blade at the front of said push member and adjacent the bottom of said blade, one of the push member connections to the blade comprising a pivotal connection, the other connection between the push member and the blade comprising a slide pivotally connected to said push member and received in a generally upwardly extending track section on said blade, said track section being arcuate about said pivotal connection as a centerof radius, extensible means acting substantially vertically between said slide and said blade for varying the tilt of saidblade about said pivotal connection, an extensible connection pivotally connected to said blade adjacent the top thereof and pivotally connected to said tractor adjacent the front thereof for varying the pitch of said blade about the connections between said push member and said blade, and further extensible means 8 pivotally connected to said blade and pivotally connected to said tractor for raising and lowering said blade.

4. A bulldozer comprising a tractor having a body and at least four wheels, at least two of which are steerable, the front wheels having a common axis when oriented for straight-ahead travel, a dozer blade having a vertical center axis, a lower push member of rectangular outline comprising a pair of spaced apart parallel slide arms rigidly interconnected, said side arms being pivotally connected to said body forwardly of said front wheel common axis, said side arms being respectively connected to said dozer blade relatively adjacent the bottom thereof and substantially symmetrically about the vertical center axis thereof, one of said connections being a universal connection and the other comprising an upright arcuate tracks on said blade and a slide pivoted to the corresponding arm and interfitting in said track, the slide being pivotable relative to the corresponding arm about a horizontal axis, means for relatively raising and lowering said track and said slide for varying the tilt of said blade, an upper arm of variable length pivotally connected to said blade relatively adjacent the top thereof and to said body, said upper arm being effective to vary the pitch of said blade, and extensible means pivotally connected to said blade and to said body for raising and lowering said blade.

5. A bulldozer as set forth in claim 4 wherein the side arms of said push member are rigidly interconnected substantially throughout their entire length.

6. A bulldozer as set forth in claim 4 wherein the means for relatively raising and lowering said track and said slide comprises an upright extensible member connected to aid slide and to said blade.

'7. A bulldozer as set forth in claim 4 wherein the arm connected to said slide comprises an extensible arm for varying the angle of said blade.

8. A bulldozer as set forth in claim 4 wherein the push member arm connected to the slide comprises an extensible fluid power operated means, wherein the means for relatively raising and lowering the track and slide comprises a fluid power operated means connected to said slide and to said blade at a different elevation from the connection to said slide, and wherein the upper arm of variable length and the extensible means for raising and lowering said blade comprise fluid power operated means.

9. A bulldozer as set forth in claim 4 wherein the universal connection comprises a self aligning bearing having complementary engaging concave and convex spherical surfaces.

10. A bulldozer comprising a tractor having at least four wheels, at least two of which are steerable, a dozer blade, a lower push member of substantially rectangular configuration pivotally connected at two horizontally spaced connections to said tractor adjacent the front thereof, said push member having two horizontally spaced connections to said blade at the front of said push member and adjacent the bottom of said blade, one of the push member connections to the blade comprising a universal connection, the other connection between the push member and the blade comprising a track section and a slide slidably associated therewith, one of said track and slide being connected to said push member and the other thereof being mounted on said blade, said track section extending generally'upwardly and being arcuate about said universal connection as a center of radius, extensible means acting substantially vertically between said blade and the one of said track and slide connected to said push member for varying the tilt of said blade about said universal connection, an extensible connection pivotally connected to said blade adjacent the top thereof and pivotally connected to said tractor adjacent the front thereof for varying the pitch of said blade about the connections between said push member and said blade, and

further extensible means pivotally connected to said blade and pivotally connected to said tractor for raising and lowering said blade.

References Cited by the Examiner UNITED STATES PATENTS Cummings 37-144 X Humphrey 37-42 Felt 37-144 Le Tourneau 37-144 Kucharr 37-144 Washbuno 37-144 Rockwell 37-144 Mork 37-144 Troop 37-144 Pilch 37-117.5 X Wills 37-42 X 1 0 1/1956 Cassidy 37-144 6/ 1956 Nave 37-144 1/ 1957 Rockwell 37-144 4/1957 Manning 37117.5 11/1958 Toulmin 37-117.5 3/1960 Blomquist 37-144 X 3/ 1960 Skromme 37-144 3/1961 Bernotas 37-144 1/1962 McAdams 37-144 4/1963 Beckford 37-144 FOREIGN PATENTS 3/ 1954 Australia.

15 ABRAHAM G. STONE, Primary Examiner.

BENJAMIN HERSH, ARNOLD RUEGG, ANTONIO F. GUIDA, Examiners. 

1. A BULLDOZER COMPRISING A TRACTOR HAVING AT LEAST FOUR WHEELS, AT LEAST TWO OF WHICH ARE STEERABLE, A DOZER BLADE, A LOWER PUSH MEMBER OF SUBSTANTIALLY RECTANGULAR CONFIGURATION PIVOTALLY CONNECTED AT TWO HORIZONTALLY SPACED CONNECTIONS TO SAID TRACTOR ADJACENT THE FRONT THEREOF, SAID PUSH MEMBER HAVING TWO HORIZONTALLY SPACED CONNECTIONS TO SAID BLADE AT THE FRONT OF SAID PUSH MEMBER AND ADJACENT THE BOTTOM OF SAID BLADE, ONE OF THE PUSH MEMBER CONNECTIONS TO THE BLADE COMPRISING A UNIVERSAL CONNECTION, THE OTHER CONNECTION BETWEEN THE PUSH MEMBER AND THE BLADE COMPRISING A SLIDE PIVOTALLY CONNECTED TO SAID PUSH MEMBER AND RECEIVED IN A GENERALLY UPWARDLY EXTENDING TRACK SECTION ON SAID BLADE, SAID TRACK SECTION BEING ARCUATE ABOUT SAID UNIVERSAL CONNECTION AS A CENTER OF RADIUS, EXTENSIBLE MEANS ACTING SUBSTANTIALLY VERTICALLY BETWEEN SAID SLIDE AND SAID BLADE FOR VARYING THE TILT OF SAID BLADE ABOUT SAID UNIVERSAL CONNECTION, AN EXTENSIBLE CONNECTION PIVOTALLY CONNECTED TO SAID BLADE ADJACENT THE TOP THEREOF AND PIVOTALLY CONNECTED TO SAID TRACTOR ADJACENT THE FRONT THEREOF FOR VARYING THE PITCH OF SAID BLADE ABOUT THE CONNECTIONS BETWEEN SAID PUSH MEMBER AND SAID BLADE, AND FURTHER EXTENSIBLE MEANS PIVOTALLY CONNECTED TO SAID BLADE AND PIVOTALLY CONNECTED TO SAID TRACTOR FOR RAISING AND LOWERING SAID BLADE. 